IDPA Membership: $40
IDPA RSO Cost: My class was $100 but varies
IDPA Match: Monthly is $15 and $10 for an additional shoot. Free with RO help.
IDPA Equipment: Since I carry AIWB I require compeition specific equipment and use a Comp-Tac International ($80) but a standard Bladetech on Amazon is $25 and 99% the same aside from attachment choices that most don't need. Since I am using competition equipment for a holster I do the same with a cover garment and use an EOTac vest. They're outta business so the equivalent would be $50-75 for a Woolrich/5.11/similar. For pouches I use Kytex Shooting Gear. They're cheap and they work.